1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
|
/*
* arch/arm/plat-spear/pl080.c
*
* DMAC pl080 definitions for SPEAr platform
*
* Copyright (C) 2012 ST Microelectronics
* Viresh Kumar <vireshk@kernel.org>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
*/
#include <linux/amba/pl08x.h>
#include <linux/amba/bus.h>
#include <linux/bug.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock_types.h>
#include <mach/spear.h>
#include <mach/misc_regs.h>
static spinlock_t lock = __SPIN_LOCK_UNLOCKED(x);
struct {
unsigned char busy;
unsigned char val;
} signals[16] = {{0, 0}, };
int pl080_get_signal(const struct pl08x_channel_data *cd)
{
unsigned int signal = cd->min_signal, val;
unsigned long flags;
spin_lock_irqsave(&lock, flags);
/* Return if signal is already acquired by somebody else */
if (signals[signal].busy &&
(signals[signal].val != cd->muxval)) {
spin_unlock_irqrestore(&lock, flags);
return -EBUSY;
}
/* If acquiring for the first time, configure it */
if (!signals[signal].busy) {
val = readl(DMA_CHN_CFG);
/*
* Each request line has two bits in DMA_CHN_CFG register. To
* goto the bits of current request line, do left shift of
* value by 2 * signal number.
*/
val &= ~(0x3 << (signal * 2));
val |= cd->muxval << (signal * 2);
writel(val, DMA_CHN_CFG);
}
signals[signal].busy++;
signals[signal].val = cd->muxval;
spin_unlock_irqrestore(&lock, flags);
return signal;
}
void pl080_put_signal(const struct pl08x_channel_data *cd, int signal)
{
unsigned long flags;
spin_lock_irqsave(&lock, flags);
/* if signal is not used */
if (!signals[signal].busy)
BUG();
signals[signal].busy--;
spin_unlock_irqrestore(&lock, flags);
}
|
